how to set 4 space indent in emacs - emacs

Question

every time I add a new line, it would indent automatically but it indents 2 spaces, not 4 spaces.
Below is my .emacs snippet.
(defun make-vline-xpm (width height color &optional lor)
(let* ((w width)
(h height)
(s1 (concat "\"" (make-string w (string-to-char " ")) "\""))
(s2 (cond
((eq lor 0)
(concat "\"." (make-string (1- w) (string-to-char " ")) "\""))
((eq lor 1)
(concat "\"" (make-string (1- w) (string-to-char " ")) ".\""))
((null lor)
(concat "\"" (make-string (- (1- w)(/ (1- w) 2))(string-to-char " "))
"." (make-string (/ (1- w) 2)(string-to-char " ")) "\""))))
(sa (concat s1 ",\n" s2 ",\n")))
(eval `(concat "/* XPM */
static char * dot_vline_xpm[] = {
\"" (number-to-string w) " " (number-to-string h) " 2 1\",
\" c None\",
\". c " color "\",\n"
,#(mapcar (lambda(x) sa)
(make-list (1- (/ h 2)) 0))
s1 ",\n" s2 "};"
))))
(defvar indent-vline-img (make-vline-xpm 9 20 "#4D4D4D"))
(defun draw-indent-tab (beg end &optional color)
(if window-system
(set-text-properties
beg end
`(display (image
:type xpm
:data ,indent-vline-img
:pointer text
:ascent center
:mask (heuristic t))
rear-nonsticky (display)
fontified t))
(compose-region
beg end
(prog1 "|"
(set-text-properties beg end '(font-lock-face (:foreground "#4D4D4D"))))
'decompose-region)))
(defun draw-indent-vline ()
(interactive)
(save-excursion
(beginning-of-line)
(let* ((i (current-indentation))
(l (save-excursion
(count-lines (point)
(forward-list)))))
(while (> l 0)
(let* ((p1 (progn (move-to-column i)(point)))
(p2 (1+ p1)))
(if (and (eq (get-byte p1) 32)
(save-excursion
(skip-chars-backward " ")(bolp)))
(draw-indent-tab p1 p2))
nil)
(forward-line)
(setq l (1- l))))))
(defun indent-vline-lisp ()
(interactive)
(funcall
(lambda (x)
(font-lock-add-keywords
nil `((,x
(0 (draw-indent-vline))))))
"^[ \t]*[,`#'(]")
(defadvice delete-char (after indent-vline activate compile)
(save-excursion
(let* ((p (point))
(q (skip-chars-forward " "))
(x (progn (skip-chars-backward " ")(bolp))))
(if x
(remove-text-properties p (+ p q) '(display)))))))
(defun indent-vline ()
(interactive)
(funcall
(lambda (x)
(font-lock-add-keywords
nil `((,x
(0 (if (save-excursion
(skip-chars-backward " ")(bolp))
(let* ((p1 (point))
(p2 (1+ p1)))
(if (or (null (eq (get-byte p1) 32))
(get-text-property p1 'display))
nil
(draw-indent-tab p1 p2)
nil))))))))
" \\( \\)")
(defadvice delete-char (after indent-vline activate compile)
(save-excursion
(let* ((p (point))
(q (skip-chars-forward " "))
(x (progn (skip-chars-backward " ")(bolp))))
(if x
(remove-text-properties p (+ p q) '(display)))))))
I do not know lisp language. This .emscs is copied from others'. So my problem is how to set 4 space indent?
I have tried to add below to my .emacs, but it does not work.
(setq-default indent-tabs-mode nil)
(setq-default tab-width 4)
(setq indent-line-function 'insert-tab)

Answer 1

How about using custom-set-variables:
(custom-set-variables
'(tab-width 4))